Bioinspired hierarchical wrinkled PVDF@PDMS/TiO2 nanofibrous membrane for highly efficient emulsion separation under harsh conditions

Inspired by the multi-scale wrinkled patterns observed on tree bark surfaces, a novel approach was developed to enhance oil–water selectivity in emulsion separation by constructing nanoscale rough structures on membrane surfaces, endowing them with superhydrophobic and superoleophilic properties. Specifically, PVDF electrospun nanofibrous membranes were coated with a composite layer composed of polydimethylsiloxane (PDMS) and TiO 2 nanoparticles through a simple one-step dip-coating method, resulting in the formation of PVDF@PDMS/TiO 2 membranes featuring heterogeneous interfaces. Through heat treatment at 120 °C, a durable three-dimensional textured surface was fabricated, exhibiting a water contact angle of 170.2°, which confirms its remarkable superhydrophobic properties. The membrane demonstrated outstanding performance in oil–water separation, achieving a separation efficiency greater than 99%, a high flux of 1100 L m⁻ 2  h⁻ 1 , and effective removal of organic dyes through the photocatalytic activity of TiO 2 . Antibacterial testing demonstrated over 99% inhibition effectiveness against both Staphylococcus aureus and Escherichia coli . Moreover, the membrane retained a contact angle above 160° when exposure to strong acidic or alkaline conditions, indicating excellent chemical stability. These characteristics suggest that the developed multifunctional nanofibrous membrane with a hierarchical wrinkled structure exhibits significant potential for the efficient treatment of complex industrial oily wastewater systems. Graphical abstract